Alternating piston type engine



May 15, 1962 c. M. MOORE 3,034,449

ALTERNATING PISTON TYPE ENGINE Filed April 8, 1960 5 Sheecs$heet 1 ATTORNEYS May 15, 1962 c. M. MOORE ALTERNATING PISTON TYPE ENGINE 5 sheets-sheet? Filed April 8, 1960 IN V EN TOR. MI M00119 A TTORNEYS May 15, 1962 c. M. MOORE ALTERNATING PISTON TYPE ENGINE HTTORNEYS 5 Sheets-Sheet 3 Filed April 8, 1960 y 1962 c. M. MOORE 3,034,449

ALTERNATING PISTON TYPE ENGINE Filed April 8, 1960 5 Sheets-Sheet 4 56 m 96 2 a 55 L74 we /54 w LZyde M Moare HTTURVWEYS y 1962 c. M. MOORE 3,034,449

ALTERNATING PISTON TYPE ENGINE Filed April 8, 1960 s Sheets-Sheet 5 INVENTOR. j gyde M mare H TTORNE Y5 United rates Patten 3,634,449 1 ALTERYATING PESTQN 'ETYPE. ENGlNE Clyde Maurice Moore, 1204 Lake Ave, Richmond, Va. Filed Ap 8, 1960, Ser. No. 2%,?59 18 Claims. (Cl. 163-429} This invention relates to alternating piston type engines, and more specifically to an engine of the alternating piston type employing one or more pairs of pistons operating in an annular chamber, the pistons having variable speeds whereby one piston functions as the movable member and the other as an abutment to provide a variable volume expansion or compression chamber during one portion of a cycle, and the other piston functions as a movable member and the one piston functions as the abutment during another portion of the cycle. Engines of this type are referred to in the art as alternating piston type because of the operation wherein any one piston alternately functions as an abutment and as the working member in an expansible chamber. The word engine is used herein in its broader sense to include pumps, compressors, expansible chamber motors operated by compressed gas or a liquid under pressure, meters, and combustion engines of the internal or external combustion type.

Engines of this type depend upon various forms of mechanical transmission to translate the alternating variable speeds of the pairs of pistons to a constant speed power output shaft in a combustion engine or fluid operated motor, or to translate the constant speed of a power input shaft to an alternating variable speed of the pistons in the case of a pump or compressor. Various forms of transmissions have been suggested, which sufier from one or more disadvantages, and as a result, this type of engine, which appears to lend itself so admirably to a pump, compressor, fluid pressure expansion motor, internal cornbustion engine or external combustion engine, has failed to attain any measure of st cess. lrior art transmissions fall into one of the following categories: (1) cams, internal or external, or combined; (2) cranks, and (3} intermittent grip devices. The cams and intermittent grip devices are subject to jerking movement of the parts, which produces objectional vibrations and unbalanced forces, while the cranks fail to provide a satisfactory alternating movement which requires that the abutment piston remain practically stationary or to rotate very slowly in the same direction as the working piston.

It is an object of the invention, therefore, to provide a novel engine of the alternating piston type which is practically free from vibrations and objectionable jerky movement of the pistons.

It is a further object to provide a novel engine of the type indicated in which the piston which functions as an abutment is substantially motionless or moving at a very slow velocity while the other piston moves at substantially the same velocity as the input or output shaft.

It is a further object to provide a novel engine of the type indicated in which the alternating motion of the pistons is produced by a pantographic system of linkages.

It is a further object to provide, in an engine of the type indicated, a novel mounting for a ring gear which reduces vibrations and shock loads to a minimum.

It is a still further object to provide a novel engine of the type indicated in which the mechanism for translating the alternating motion of the pistons to a uniform unidirectional motion of the output shaft is confined within the axial limits of the cylinder housing to effect a marked saving in space.

It is a still further object to provide a novel engine of the type indicated in which any number of units can be connected to a common shaft to provide a plural cylinder Patented May 15, 1962 engine, requiring the use of only a minimum number of different castings for the housing.

ith the foregoing and other objects in view which will appear in the following specification, the invention resides in the novel combination and arrangement of parts and/or the details of construction hereinafter described and claimed, and illustrated in the accompanying drawings, in which:

FIG. 1 is a sectional view on the line 1-1 of FIG. 2 of an internal combustion engine embodying the principles of the invention;

FlG. 2 is a transverse sectional view on the line 22 of PEG. 1 showing a portion of the transmission;

FIG. 3 is a transverse sectional view on the line 33 of FIG. 1 showing a different portion of the transmission;

FIG. 4 is a transverse sectional view on the line 4-4 of FIG. 1 showing parts of the transmission in full lines and showing the relationship of the pistons in broken lines, a portion of the cylinder wall being broken away to more clearly illustrate a piston;

FIGS. 5 to 10 show schematic representations of the transmission and pistons to graphically illustrate the relative positions of the parts through a cycle of operation, in which:

FIG. 5 illustrates the point of ignition;

FIG. 6 illustrates the relative positions after the power output shaft has traveled 30;

FIGS. 7, 8, 9 and 10 illustrate the relative positions after the power output shaft has traveled 60, and respectively;

FIG. 11 illustrates a detail of a resilient mounting for the ring gear;

FIG. 12 illustrates a modification of the engine in which the mechanism for translating the alternating motion of F the pistons to a uniform, unidirectional, motion of the output shaft is confined, in axial limits, to the space occupied by the cylinder housing;

FIG. 13 illustrates a modified construction of the engine of FIG. 12, in which the engine is air-cooled; and

FIG. 14 illustrates a multiple cylinder engine, of the type shown in FIG. 12, made up or" two different forms of castings for the cylinder housings.

Referring to the drawings, and more particularly to FIG. 1, in which the engine in its entirety is designated by the reference numeral 20, there is shown a three-part housing comprising an outer stator housing 2.2, an intermediate stator housing 24, and a transmission housing 26. These housings are retained in assembled relation by a plurality of cap screws 28 passing through aligned bores in circumferential flanges on the housings and threadedly en gaging the housing 26. Cooling fins 3% are provided on the housings to dissipate heat to the ambient atmosphere.

The housings 22 and 26 have central extensions 32 and 34, respectively, which receive plain bearings 36 and 38 in which a power shaft 49 is rotatably journaled, the shaft having end extensions beyond the bearings as shown.

A sealing ring 42 is mounted in a recess in one end of the housing 24 and cooperates with an adjacent end of the housing 22 to prevent leakage between the two housings, and a similar ring 43 in a recess in the other end of the housing 24 cooperates with an adjacent end of the housing .26 to form a fluid-tight seal between the housings 24 and 26. Openings in the rings 42 and 43 permit the passage of the cap screws 28.

The inner end of the housing 26 is rabbeted at 44 to receive a ring gear 46 of a planetary gearing transmission to be described hereinafter. Openings in the ring gear 46 permit the passage of the cap screws 28, so that the cap screws, when tightened, retain the ring gear 46 in position between the housings 24 and 26.

Opposing walls of the housings 22 and 24 are provided with recesses 48 and 50, respectively, forming an annular radially inwardly of the recesses 48 and 56 are in spaced relation to accommodate a pmr of rotor disks 52 and 54, which disks are in abutting relation with each other and with the opposed surfaces of the housings 22 and 24. Rotor disks 52 and 54 carry, on their outer edges, arcuate flanges 56 and 58, respectively, which extend in opposite directions to form a part of the wall of the chamber 51, being received within recesses 64 and 65 of the housings 22 and 24, respectively. The rotor disks 52 and 54 also carry intermediate flanges 60 and 62, respectively, having abutting shoulders, and the rotor disk 52 has an annular recess, immediately outwardly of the flange 61 to receive a sealing ring 66 cooperating with the rotor disk 54 to form a fluid-tight seal between the rotor disks. .The floors of the recesses 64 and 65 have annular grooves to receive sealing rings 66 adapted to cooperate with the end flanges 56 and 58 to prevent leakage from the chamber 51.

The radial inner ends of the rotor disks 52 and 54 are provided with axially extending hollow sleeves 68 and 79, which project in opposite directions, and which have dif- 7 'ferent diameters as shown. A tubular shaft 72, having an internal diameter slightly greater than the diameter of the power shaft 40, surrounds the shaft 40 and is keyed to the sleeve 68 at '74 to rotate with the rotor disk 52. Tubular shaft 72 is rotatably supported on the power shaft 40 by a plain bearing 76 on the right-hand end, and by a ball hearing 78 on the left-hand end. A second tubular shaft 81 shorter than the shafts 40 and 72, is rotatably supported coaxially of said latter shafts by a plain bearing 84 be- .tweenthe shafts 72 and 80, and by a ball bearing 86 between the shaft 80 and an axial extension 88 of the housing 24, Tubular shaft 80 is keyed to the rotor disk 54 by the keys 82 to rotate therewith.

Each rotor disk 52 and 54 carries a pair of diametrical- 1y opposed radial arms 90 to each of which one of the pistons P1, P2, P3 and P4 is connected by a pin 92. The pistons are circular in cross-section and arcuate in length, to provide a working fit in the chamber 51. Piston rings 93 carried in grooves in the pistons cooperate with the wall of the chamber 51 to prevent leakage.

Referring to FIGS. to 10, an induction opening 94 and an exhaust opening 96 are provided in a peripheral wall of the chamber 51, these openings being arcuately spaced a distance about equal to the arcuate length of a piston, as shown in FIG. 8. An igniter 89 (FIG. 1), in the form of a spark plug, occupies an ignition area (FIG. 5), located about 180 from a point midway of the induction and exhaust passages.

The planetary gearing (FIGS. 1 and 2) transmission includes the ring gear 46, described above, having internal teeth 110, and a rotating sun gear 100 having external teeth 102. The sun gear 100 is'keyed to the power shaft 40 at 194, and is generally in the form of the figure 8, having two intersecting circular portions 106 and 108. The ring gear 46 isof the same form as the sun gear 109. a

The tubular shafts 7'2 and 80, on the ends remote from the rotor disks 52 and 54 (FIGS. 3 and 4), are

each provided with a pair of radial arms 112 and 114, respectively, the arms on each tubular shaft being disposed 180 apart (FIG. 3) and being in the same axial planes as the radial arms 90. The outer or free ends of the radial arms 112 and 114 have pivotal connections 116 and 118, respectively, which connections are the same radial distance from the center of the shaft 40. The pivotal connections 116 of the radial arms 112 are connected at the mid-points of the links 122 and 126, and the pivotal connections 118 of the radial arms 114 are connected at the mid-points of the links 120 and 124. Four planet gears 1 28, 130, 132 and 134 are pivotally connected to the links as follows: the planet gear 128 is connected to is considered.

one end of the links 12% and 122; the planet gear 130 is connected to one end of the links 122 and 124; the planet gear 132 is connected to one end of the links 124 and 126; and the planet gear 134 is connected to one end of the links 1219 and 126.

Each planet gear comprises a large pinion 136, engageable with the internal teeth on the gear 46, and a smml pinion 138 engageable with the external teeth 102 on the rotating sun gear 100. The pinions 136 and 138 are rigidly mounted on a shaft 140 for rotation therewith and the shafts 14b constitute pivot pins for the links nil-426. From the foregoing, it is evident that the links 12:), 122, 124 and 126 are connected in the form of a parallelogram having equal sides, each of the connecting ends rotatably carrying a planet gearyand a midpoint of each link pivotally connected to one of the radial arms 112 or 114. It'is also evident that, during rotation of the parallelogram, the angles between the links vary from acute to obtuse, resulting in a variable separation between the pivotal connections 116 and 118, as will be described in greater detail hereinafter.

The acceleration and deceleration, at certain points in the orbital path of the pistons, areetfected by the novel transmission disclosed, which also provides novel coordination between the pistons and the shafts, at points other than the acceleration and deceleration, whereby the respective pairs of pistons are alternately compelled to progress, in orbit, at substantially the same rate of speed as the power shaft, without either of the respective pairs of pistons being directly connected to the shaft as in the prior art.

In the description of operation which follows, a modification relating to a 4-cycle rotary combustion engine It should be understood, however, that the principles of operation are equally applicable to a 2- cycle internal combustion engine, as well as to a fluid pressure rotary motor, a rotary compressor, a rotary pump, or rotary meter.

Referring to FIG. 5, which shows the parts with the pistons P1 and P3 at their points of maximum convergence, the pistons P2 and P4 at their points of maximum convergence, and the transmission occupying the position shown in FIGS. 1 to 4, a fuel charge is compressed between the pistons P1 and P3, while the piston P4 partially uncovers the exhaust opening 96, permitting the escape of the burned gases between the pistons P1 and P4, and the piston P2 partially uncovers the induction opening 94, permitting a fuel charge to enter the chamber 51 between pistons P2 and P3. In this figure, as well as in the following figures, the path of the center of shafts 140 relative to the stationary ring gear is shown in solid lines, while the path of the center of shaft 140 relative to the rotating sun gear appears in phantom lines. The centers of shafts 140 must, therefore, be at the points of intersection of the solid and phantom lines. The path of movement of the pivotal connections 116. and 118 between the radial arms 112 and 114 with the midpoints of the links of the parallelogram is in the form of a circle shown in broken lines. With reference to'FIG. 5, it will be noted that the pinions 128 and 132 are at the halfway mark around the circles 196 and 108, while the pinions 130 and 134 are at the intersection of these circles. and as a result the pivotal connections 116 and 118 attain their maximum proximity or convergence. Assuming that ignition occurs when the parts are in position shown in FIG. 5, or slightly before or after, the resulting increase in pressure between the pistons P1 and P3 caused by combustion of the compressed fuel charge will produce a force on the pivotal connections 116 in a clockwise direc tion and an equal force on the pivotal connection 118 in a counterclockwise direction. With reference to FIG. 3, these opposed forces will produce a pivoting of the links and 122 about the shaft 140 of pinion 128, and a pivoting of the links 124 and 126 about the shaft 140 of pinion 132, which, in turn will cause the planet gear to roll into the lower right portion of the ring gear 46 and cause the planet gear 134 to roll into the upper left hand portion of the ring gear, producing a component tending to cause rotation of the pinions 136 and 138 in counterclockwise direction. This action will cause the planet gears to orbit in a clockwise direction around the shaft 40, producing a consequent clockwise rotation of the sun gear 100 at twice the speed of revolution of the planet gears. This is clearly evident from an inspection of FIG. 6, in which the sun gear 100 has rotated through an angle of 30 from the position of FIG. 5. It will be noted that the piston P3 is moving very slowly in a clockwise direction, but that the piston P1 is moving much more rapidly in the same direction, and that the distance between the pivotal connections 116 and 118 is increasing, as well as the distance between the planet gears 130 and 134, while the distance between the planet gears 128 and 132 is decreasing. The pistons P1 and P2 are traveling at substantially the same speed as the sun gear. Piston P4, which is traveling at the same speed as the piston P3, has uncovered the exhaust opening 96 to a greater extent whereby the piston P1 is scavenging the exhaust gases ahead of it. At the same time, the piston P2, which is traveling at the same speed as the piston P1, is inducing a fuel charge through the induction opening 94 while compressing a previously induced charge behind the piston P3. The planet gears 130 and 134 have entered the circular portions of the ring gear 46 and are moving outwardly in nearly a radial direction.

FIG. 7 illustrates the relationship of the parts after the sun gear 100 has rotated through an angle of 60 from the position of FIG. 5. From a comparison of FIG. 7 with FIG. 6, it will be observed that the pistons P3 and P4 have moved very slowly in a clockwise direction, while the pistons P1 and P2 continue to move at substantially the same speed as the sun gear. The burning gases continue to expand between the pistons P1 and P3, performing a power output stroke, the piston P1 continues to scavenge the exhaust gases ahead of it, while the piston P4 induces a fresh charge on its trailing face and compresses a previously induced charge between its forward face and the trailing face of piston P3. The planet gears 13') and 134 continue to diverge while rolling in the circular portion of the ring gear, causing the sun gear 100 to rotate in a clockwise direction.

FIG. 8 shows the relationship of the piston and transmission after the sun gear 100 has rotated through an angle of 90 from the position of FIG. S. The pistons P1 and P2 have also rotated through the same angle, while the pistons P3 and P4 are at to 180 positions, respectively, with the piston P4 occupying a position be tween the induction opening 94 and the exhaust opening 96. The links of the parallelogram assume the form of a square, and the planet gears 130 and 134 continue to diverge while moving outwardly in the circular portions of the ring gear 46. At the same time the planet gears 128 and 132 continue to move toward one another. The pistons P1 and P2 continue to rotate at the same speed as the sun gear 100, and the pistons P1, P2, P3 and P4 are performing the same functions as in FIGS. 5, 6 and 7.

FIG. 9 shows the positions of the pistons and transmission after 120 rotation of the sun gear from the position of FIG. 5, in which the pistons P3 and P4 continue to rotate clockwise at a very slow speed, while the pistons P1 and P2 continue to move at substantially the same speed as the sun gear 100. All of the pistons perform the same functions as previously described. Planet gears 130 and 134 continue to diverge, and planet gears 128 and 132. continue to converge.

FIG. 10 illustrates the relationship of the pistons and transmission after the sun gear 100 has traveled through 150 from the position of FIG. 5. The pistons P3 and P4 continue to rotate clockwise at substantially the same slow speed, while the pistons P1 and P2 continue to rotate at substantially the same speed as the sun gear. In this position of parts, the pistons P1 and P4 are approaching the maximum convergence and the same is true concerning the pistons P2 and P3. At about this position, the pistons P1 and P2 rapidly decelerate, as the piston P4 moves toward the position occupied by P2 in FIG. 5 and the piston P1 moves toward the position occupied by the piston P4 in said latter figure. When the pistons reach this position, as shown in FIG. 5, the exhaust gases between the pistons P3 and P1 will be permitted to discharge from the exhaust passage 96, the piston P4 will move to close the induction passage 94 to initiate compression of the fuel charge between the pistons P4 and P2, while a fresh fuel charge will be induced between the pistons P4 and P1. The highly compressed fuel charge between the pistons P2 and P3 will be moved to the position occupied by the pistons P3 and P1 in FIG. 5, at which time the fuel charge will be ignited and the piston P3 will then become the power output member.

It will be noted, with reference to FIGS. 5' to 10, that the sun gear has completed a full rotation, while the pistons have traveled through substantially It will also be observed, because of the parallelogram structure of the linkages, that the pistons have been given a variable speed movement, which is always in a clockwise direction, and that the working piston P1 and the compression piston P2 are rapidly accelerated from the position shown in FIG. 5 to travel at substantially the same speed as the sun gear, which speed continues until the pistons P1 and P2 reach the position shown occupied by the pistons P4 and P3, respectively, in FIG. 5, at which time there is a rapid deceleration. From an observation of FIGS. 5 to 10, it will also be observed that the pistons P1 and P2 do not travel at exactly the same speed as the sun gear, but at substantially the same speed. After the sun gear has completed one rotation, during which time the planet gears have orbited through one-half a revolution, the pistons which then become the power and compression pistons are rapidly accelerated to rotate at the same speed as the sun gear, while the other two pistons, which function as abutment pistons, rotate at a very slow speed in a clockwise direction. From the foregoing, it is evident that the pistons P1, P3, P2- and P4 follow in succession as power pistons and the pistons P2, P4, P1 and P3 simultaneously function as compression pistons, and while any pair of interconnected pistons function as power and compression pistons, respectively, the other two pistons function as abutment pistons. The pistons also function as valving members to control the induction passage 94 and the exhaust passage 96.

From the foregoing, it is evident that I have invented a novel alternating piston type engine in which the power and compression pistons are first rapidly accelerated to a speed substantially the same as the power shaft, and, having traveled nearly 180, are quickly and smoothly decelerated, while the other pistons, which previously served as abutment pistons, then become power and compression pistons and are similarly smoothly and rapidly accelerated to the speed of the output shaft, and then decelerated. This operation assures a smooth transmission of power, without the objectionable jerking which made previously suggested power plants of this type impracticable. The acceleration and deceleration are effected by the novel transmission disclosed, which also provides a 2. to 1 speed ratio between the power shaft and the pistons.

In the case of a fluid pressure motor, or a pump or compressor, the ignition area can be omitted, and a second pair of induction and exhaust ports 94 and 96 can be provided 180 from those shown in FIGS. 5 to 10. The operation of the disclosed rotary combustion engine on a 2-cycle principle would require the addition of a means to introduce a pro-compressed charge between the power piston and its abutment piston.

FIG. 11 illustrates a detail of a resilient mounting for a the ring gear 46, which is applicable to any of the em bodiments disclosed.

The ring gear 46 includes a pair of diametrically disposed elongated slots 141, one of which appears in FIG. 11. A pair of L-shaped brackets 142 are mounted, by. rivets 144 or the like, on the wall of the ring gear, so that a leg 143 of each bracket extends through each end of the slot 141. A pair of fixed abutments 145, diametrically disposed, are mounted on the housing adjacent the ring gear in such a position that each abutment extends through one of the slots 141 in a position parallel to and equally. spaced from the legs 143. A pair of springs 146' r are interposed between each fixed abutment 145 and the spaced legs 143. In this arrangement, the cap screws 28 do not restrain the ring gear 46 against movement, since arcuateslots 147 are provided in the ring gear through which the cap screws 28 extend to permit angular movement of the ring gear by compression and expansion of the springs 146, thereby providing a resilient and shockabsorbing connection.

A, modified form of engine is illustrated in FIG. 12, in which parts corresponding to those appearing in the first embodiment are identified by the same reference numerals including the superscript prime.

The engine '20 comprises a pair of sirnilar housing members 150 and 152 having parallel radial flanges 154 and 156, respectively, which are secured in face-to-face relation by a series of cap screws 158. The wall of the flange 156 is recessed to receive an annular seal 160 to prevent leakage from the engine cylinderbetween the two housing members. The'housing members include interconnected cooling jackets 162 through which a coolant circulates.

Each housing includes'a central extension 34' which is bored at 164 for the passage of a power output shaft 40'. The bores 164 are greater in diameter than the shaft 40' to accommodate seals 166, which areretained in place by plates 1-68 and cap screws 170. The bores 164 are coun terbored at 172 to receive tapered roller bearings 174 rotatably supporting lthe shaft 40'.

V Opposing faces of the housings 150 and 152 are pro vided with annular recesses 48 and 50, which are semicircular in cross section and cooperate to form an annular chamber 51' in which the pistons revolve, as will be described hereinafter. The opposed surfaces of the housings 150 and 152, radially inward of the recesses 48' and 50', are spaced apart to accommodate a'pair of annular rings 52 and 54', which correspond in function to the rotor disks 52 and 54 in the first embodiment, the rings being in abutting relation with each other and with the opposed surfaces of the housings 150 and 152 adjacent the annular chamber 51. The annular rings carry, on their outer edges, arcuate flanges 56' and 58', which are received in rabbets in the recesses 48' and 50, whereby the flanges form a portion of the wall of the annular chamber. Sealing rings 66' engage an undersurface of the flanges 56 and a 58' to prevent leakage.

Each annular ring 52' and 54 carries a pair of pistons (not shown) spaced 180 apart, corresponding to the pistons P1, P2, P3, and P4 of the firstembodiment, and the housing 150 is provided with an induction inlet and an exhaust outlet, corresponding to the inlet 94 and outlet 96 in the first embodiment of which only the exhaust outlet 96' is shown. Housing 150 has a threaded bore to receive an igniter 98, angularly spaced about 180 from the inlet and outlet.

The annular rings 52 and 54 are integral with the pivotally mounted radial arms 112 and 114', which construction is the equivalent of the construction including the connections 72 and 80 of the first embodiment; The arms 112 and 114, in turn, are connected, at their outer ends, to the pivotal connections 116' and 118', respectively.

'In this embodiment, the annular rings 52' and 54 are substantially identical. The four interconnecting links 8 120', 122', 124' and .126 are identical, and, therefore, the entire pantographic linkage, which includes the annular rings 52 and 54', and the projecting arms carrying the pistons, involves only two basic parts or forgings.

The pivotal connections 116' and 118 are mounted at the midpoints of a pantographic' system of linkagm similar to thatof the first embodiment, including planet gears at the ends of the links and 122', of which only the planet gears 132 and 134 are shown, mounted on shafts Each planet gear includes a pair of large pinions 136', one on each end of the shaft 140', and a pair of small pinions 138', inwardly of the large pinions, the large and small pinions on each end being non-rotatably connected to each other and to the ends of the shaft 140'. Each pinion 136 engages the internal teeth 110'. on a corresponding one of a pair of ring gears 46', anchored in suitable recesses in the housings and 152, the ring gears 46 corresponding in form and function with the ring gear 46 in the first embodiment and which may include the features shown in-FIG. 11. Each small pinion 138' is in engagement with the external teeth of a rotating sun gear 100 which is keyed to the shaft 40' at 104?.

The operation of the embodiment shown in FIG. 12 is identical with the first embodiment, and a detailed description appears unnecessary.

FIG. 13 illustrates a modified construction of the engine of FIG. l2having a difierent form of jacket for air cooling. Corresponding elements are designated by the same reference numerals with the addition of the superscript 2.

The housing 150 includes a shroud 176 defining a cooling path 178, and the housing 152 includes a similar shroud 180 defining a cooling path 182, the two paths being connected for series flow of cooling fluid received by an inlet 184 in the center of the housing 150 and discharged through an outlet 186 in the center of the housing 152 the path of flow being indicated by the arrows. Cooling air may be delivered by a fan, not shown, driven by the shaft 40 The embodiment in FIG. 14 illustrates a construction by which an engine of three or more cylinders can be built up by utilizing only two diflerent forms of housings. The

cylinders are of the type shown in FIG. 12 in which the 7 The multi-cylinder engine 200 of FIG. 14 comprises.

identical end housings 202 and two similar intermediate housings 204 and 205, each end housing having spaced radial flanges 206 cooperable with corresponding spaced radial flanges 208 on the intermediate housings for the reception of cap screws 210 to secure the housings in abutting relation. The spaces 212 between the flanges are hollow for the passage of coolant from the jacket 214 about one housing through the jacket 214 of the adjoining housing.

The flanged periphery of each end housing is provided with an annular recess 216 to receive an annular boss 218 on the flanged periphery of an adjoining intermediate housing 204 or 205. An annularseal 220 in the recess 216 prevents leakage.

v The right hand wall of the intermediate housing 204 is provided with an annular recess 222 which receives an annular boss 224 on the left hand wall of the intermediate housing 205. A seal 226 in the recess 222 prevents leakage. Each end housing 202 is provided with an annular recess 228 of semi-circular cross section, and each intermediate section 204 and 205 is provided with opposed annular recesses 230 and 232 of the same form, which register to form annular cylinders in which the pistons 234 revolve.

The intermediate housings 204 and 205 are identical in all respects, except that the outer peripheral edges of the housing 204 have an opposed boss 218 and a recess 222, while the outer peripheral edges of the intermediate a et housing 205 have opposed annual bosses 224. It is evident that both types of intermediate housings can be machined from the same casting.

Each end housing 202 includes a relatively narrow recess 236 to receive a ring gear 238, and each intermediate housing 204 and 205 includes a wider recess 240 to receive a ring gear 242, the ring gear 242 being about twice the width of the ring gear 238. The ring gears 238 coact with the large pinions of the planet gears on the transmission for the outer cylinders, while the ring gears 242 coact with the large pinions of the planet gears on the transmission for the cylinders on both sides thereof.

Each housing includes a threaded opening for an igniter 244. The opening in the left hand housing 202 may be closed by a plug (not shown).

The right hand end housing 202, and each intermediate housing 204 and 205, includes an induction inlet and an exhaust outlet, to which are connected the ducts 246 and 248. Similiar openings (not shown) may be provided in the left hand end housing 202, which maybe plugged, or may be connected to ducts 246 and 248.

The manner of building an engine with additonal units is obvious, which requires only the addition of intermediate housings 204. A two cylinder engine can be built by using only the end housings 202 and the intermediate housing 205. Two identical end castings can be machined to form a single cylinder engine.

It will be understood that various changes may be made in the details of construction and in the arrangement of parts of the engine disclosed herein without departing from the principles of the invention and the scope of the annexed claims.

I claim:

1. An alternating piston type engine, comprising: a housing having an annular chamber therein having inlet and outlet ports; a plurality of pistons in said chamber; means interconnecting pairs'of said pistons for simultaneous rotary movement in said chamber; a power shaft; and a transmission translating a uniform rotary motion of the power shaft to a non-uniform movement of said interconnected pairs of pistons and vice versa, said transmission comprising a pantographic linkage and a planetary gearing in which the pairs of pistons rotate in the same direction, one pair accelerating while the other pair is decelerating, and vice versa, to alternately contract and expand the space between successive pistons, said gearing having a stationary gear carried by the housing, a rotating gear carried by the power shaft, and planet gear-s including at least one pair of interconnected gears meshing with said stationary and said rotating gears, respectively, said stationary and said rotating gears having a similar noncircular contours; said pantograp'nic linkage being connected to said planet gears; and means to connect the pairs of pistons to said linkage.

2. An alternating piston type engine according to claim 1, in which the pantograph comprises four links interconnected at their ends, said planet gears being supported at the interconnected ends of the links, and the connecting means between the pairs of pistons and said linkage being pivotally connected to said linkage at points intermediate the ends.

3. An alternating piston type engine according to claim 1, including means resiliently supporting a member in the transmission, whereby transmission shocks are absorbed.

4. An alternating piston type engine according to claim 1, including a resilient connection between said stationary gear and the housing, whereby the stationary gear is permitted slight angular movement to absorb transmission shocks.

5. An alternating piston type engine according to claim 1, in which the transmission is disposed in the space between the annular cylinder and the axis thereof.

6. An alternating piston type engine, comprising: a housing having an annular chamber therein including inlet and outlet ports; a plurality of pistons in said chamber; means interconnecting pairs of said pistons for simultaneous rotary movement in said chamber; a power shaft; and a transmission translating a non-uniform movement of said interconnected pairs of pistons to a uniform rotary motion of the power shaft and vice versa, said transmission comprising a pantographic linkage and a planetary gearing in which the pairs of pistons rotate in the same direction, one pair accelerating while the other pair is decelerating, and vice versa, to alternately contract and expand the space between successive pistons, said gearing having a pair of axially spaced stationary gears carried by the housing, a pair of axially spaced rotating gears carried by the power shaft axially spaced from said stationary gears, and planet gears including at least one pair of interconnected gears meshing wtih said stationary and said rotating gears, respectively, said stationary and said rotating gear-s having similar non-circular contours, the linkage being interposed between said spaced stationary gears and between said spaced rotating gears.

7. An alternating piston type engine according to claim 6, in which the power shaft is disposed concentrically of the annular chamber, and in which the transmission is disposed in said housing between the annular chamber and the shaft.

8. An alternating piston engine according to claim 7, in which a transverse axis through the transmission normal to the shaft, and a transverse axis through the annular chamber normal to the shaft, are coincident.

9. An alternating piston engine according to claim 8, in which the axial extent of the linkage does not exceed the axial extent of the annular chamber.

10. An alternating piston type engine, comprising: a two part housing, each part having a central shaft opening, said parts having cooperating surfaces to define an outer annular working chamber and a cavity radially inward of said annular workingchamber; pairs of pistons revolvably mounted in said annular chamber; a power shaft rotatably mounted in said central openings, concentrically of said annular working chamber; and a transmission connected to said pairs of pistons and to said shaft, translating a non-uniform movement of said pairs of pistons to a uniform rotary motion of said shaft and vice versa, said transmission disposed in said cavity, said transmission comprising a pantographic linkage and a planetary gearing in which the pairs of pistons rotate in the same direction, one pair accelerating while the other pair is decelerating, and vice versa, to alternately contract and'expand the space between successive pistons, said gearing having a pair of axially spaced stationary gears carried by said housing and a pair of axially spaced rotating gears carried by said shaft, said stationary gears being axially spaced from said rotating gears, and planet gears including at least one group of interconnected gears meshing with said stationary gears and said rotating gears, said stationary gears and said rotating gears having similar non-circular contours, the linkage being disposed between said spaced stationary and rotating gears.

11. An alternating piston type engine according to claim 10, including a water-cooled jacket surrounding the housing.

12. An alternating piston type engine according to claim 10, including an air-cooled jacket surrounding the housing.

13. A multicyclinder alternating piston type engine, comprising: two end housings and at least one intermedi ate housing, each housing having a central shaft opening, each end housing having on one face thereof, and each intermediate housing having, on opposed faces thereof, cooperating surfaces which, when brought into abutting relation, define outer annular chambers and concentric inner cavities, the number of chambers and cavities, respectively, being one less than the number of housings; pairs of pistons revolvably mounted in each annular chamber; a power shaft rotatably mounted in said central openings, concentrically of said annular working cham- 11 bers and cavities; and a separate transmission for each annular chamber connected to the pairs of pistons therein and to said shaft, translating a non-uniform movement of said pairs of pistons to a uniform rotary motion of' said shaft and vice versa, one transmission disposed in each cavity, each transmission comprising a pantographic linkage and a planetary gearing in which the pairs of pistons rotate in the same direction, one pair accelerating while the other pair is decelerating, and vice versa, to alternately contract and expand the space between successive pistons, said gearing having a pair of axially spaced stationary gears, one carried by each end housing, and a single stationary gear carried by the intermediate housing located between the sides thereof and cooperating with the transmissions on either side thereof a pair of rotary gears per transmission carriedby said shaft disposed between a pair of stationary gears, and planet gears including at least one group of interconnected gears meshing with a pair of rotating gears and a pair of adjacent stationary gears, said stationary and said rotating gears having similar non-circular contours, the linkage for each transmission being disposed between its respective spaced stationary and rotating gears.

14. An alternating piston type engine according to claim 13, in which each intermediatehousing and at least one end housing includes an igniter opening, and induction and exhaust ports.

15. An alternating piston type engine according to claim 13, in which the end housings are similar, and in I which the intermediate housings are similar, to minimize the number of different forms of housings for an engine.

16. An alternating piston type engine, comprising: a housing including an annular chamber therein having inlet and outlet ports; a plurality of pistons in said chamher; means interconnecting pairs of pistons for simulexpand the space between successive pistons, said gearing having a stationary gear carried by the housing, a rotating gear carried by the shaft, and at least one pair of interconnected planet gears meshing with said'stationary and said rotating gears, respectively, said stationary gear and said rotating gear each being in theform of intersecting circles forming a figure 8; said pantographic linkage being connected with said planet gears; and means connecting the pairs of pistons with said linkage.

17. An alternating piston type engine according to claim 16, in which said stationary gear has internal teeth, and the rotating gear has external teeth.

18. An alternating piston type engine according to.

claim 16, in which the transmission parts are so proportioned and related as to produce one-half of a revolution of each planet gear for each fall rotation of the rotating shaft. t

a References Cited in'the file of this patent UNI ED STATES PATENTS 309,734; Oehlmann 'Dec. 23, 1884 "1,095,034 Sanchez et a1. Apr. 28, 1914 1,112,734 Vincent Oct. 6, 1914 1,330,629 Gooding Feb. 10, 1920 r 1,889,508 Zens Nov. 29, 1932 1,904,892 Trube Apr. 18, 1933 2,050,603 Gardner Aug. 11, 1936 2,124,327 Wolstenholme July 19, 1938 2,142,706 Wolstenholme Jam-3, 1939 2,156,180 Horner Apr. 25, 1939 2,271,068 Gardner Jan. 27, 1942 2,284,186 Wolstenholme May 26, 1942 FOREIGN PATENTS a 51,874 Norway Dec. 19, 1932 419,123 GreatBritain Nov. 6, 1934 559,387 France June 14, 1923 OTHER REFERENCES Mechanics of Machinery (Ham and Crane), published by McGraw-Hill (New York), 1927, pp. 193-195, 200 and 201 relied on. a

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